Hydrocarbon alkylation process



DCC 8, 1964 .1. M. BLACK ETAL HYDRocARBoN ALKYLATION PROCESS Filed Feb.19. 1960 United States Patent andere EYERCAREN ALii-ZLATON PROCESS fichaM. Black, landoane, NX., Eames Wmburton,

Alamo, Calif., and Samuel R. Stiles, Cressiriii, NJ., assignors, bymesme assignments, to Puiirnan incorparate-d, a corporation of BelavvareFiied Feb. i9, 195i?, Ser. No. '5,843

3i (Ci. lab-633.59)

This invention relates to a process for carrying out liquid phasereactions With a liquid catalyst. In one aspect this invention relatesto a'process for carrying out liquid phase reactions with a liquidcatalyst which is immiscible with at least one of the reactants. Moreparticularly, the invention relates to a process for carrying out liquidphase reactions of hydrocarbons in the presence of an acid catalyst in amulti-zonereactor.V Still more particularly, the invention relates to aprocess forcarrying out liquid phase alkylation of hydrocarbons in thepresence of an acid catalyst and in a plurality of reaction zones.

This application is a continuation-in-part of application Serial No.387,118, tiled Gctober 20, 1953, now US. Patent No. 2,927,009. Y

in carrying out liquid phase reactions in the presence of a liquidcatalyst which is immiscible with at least one of the reactants, it isnecessary to secure intimate mixing of the catalyst and the reactant tothereby form and maintain an emulsion in which either the reactant orthe catalyst constitutes the continuous phase. In the alkylation ofhydrocarbons, Which will oe referred to as illustrative of the reactionsto which the present invention is applicable, it is necessary to elfectintimate mixing of the hydrocarbon reactants and the acid catalyst toobtain the benefits of the catalytic action of the acid catalyst; thedegree of mixing of the hydrocarbons and acid is an important factor indetermining the rate of conversion and the overall eiciency of theoperation.

In the alltylation of isoparafrin hydrocarbons with olefin hydrocarbonsinthe presence of suir'uric acid, referring to the4 alltylation ofisobutane'with butenes and/ or propylenes as an example, the olefinhydrocarbons react with the sulfuric acid While the isoparainhydrocarbons present remain in a separated phase as droplets. Thealkylation reaction takes place at the Surface of the droplets formingthe discontinuous phase of the emulsion. The degreeV of mixing of theemulsion and the resulting dispersion of isobntane droplets in theracidphase of the emulsion have an important eiect on'the amount ofconversion of reactants occurring at the surface of the isobutanedroplets. Such a process is operated with a view to forming andmaintaining a proper body of emulsion so as to assure high overallefficiency.

Carrying out the allryiation reaction, a plurality of series arranged,communicating reaction zones withinv a reactor is preferred over thesingle zone reactor. In the multi-zone type of reactor, thev acid andthe bulk of the isobutane are introduced for series fiow through thezones wherein these components are emulsiiied by mixing means in eachzone. The olen feed is supplied in parallel streams to the respectivereaction zones and to the emulsion. The emulsion and the discontinuousphase remain in the rst zone of the series until a predetermined liquid.level, established by a liquid overovr means, is reached.

The overflow from the rst reaction zone then spills over to the nextreaction zone, wherein la repetition of the above reaction and flowpattern occurs, and this procedure is repeated in each reaction zone ofthe reactor until liquid leaves the final reaction zone. From the lastrepaction Zone the product overilow passes to the hydrocarbonacidseparation section wherein these phases are separated, as for example,by settling. However, thisrnethod of effecting the flow of liquidsthrough the various reaction zones is not altogether satisfactory sincethe method frequently results in flooding the reaction zones. When thisoccurs, the liquid and the vapors intermix and cause vapor loer'ng inthe mixer. These, and other disadvantages have greatly increased thecost of operating in Y manner. Y

Concurrentl with the alkylation reaction, there isa condensationreaction of the oleiin hydrocarbons in the sulfuric acid which may be`termed hydrosulfation The condensation products of this reaction areundesirable as they reduce the yield of desired alkylate products,accumulate in the acid phase and in theemulsio'n, and impair thecatalytic activity of the acid. The hydrosulfation reaction rateincreases with the concentration of the olefin hydrocarbon reactants,the reaction temperaure and the duration of intervals between theincidents of contact between the emulsion and the oleiin. Since thealkylation reaction is to some extent reversible in the presence of acidcatalyst, the alrylate product can'decompose to low temperatures and atlov/ concentrations of olenhy- Y drocarbons reactants. Thus, it isimportant to maintain in the reaction zone a relatively highconcentration of isobutane and as high a ratio of isobutane to oleiinasis practicable. To this end, an isobutane tb oleiiri feed rate ratio'ofabout 6 to 10:1 is commonly employed, although a higher isoparatlinexcess is desirable in the reaction zone. f

lit has been found in accordance ,with the presentinvention, that thereaction between the isoparaiin hydrocarbons and the olen hydrocarbonsis drivenrpr'eporiderantly in the direction of the alkylate product andthisl formation ofundesirable'by-productadue to the hydrosulfation`reaction, is reduced to a minimum when a high isoparafn-olen ratio,ismaintainedjn ther'regio'n ofV in'- trodnctionand intermixrngfo'f'theolefin lliydrocarbori` 'ihtolY the isoparaim hydrocarbon-'acid emulsion.Heretofo're,

it hasV been necessary ,to introduce and circulate abnormally largevolumesof isoparaiin and-acidinth' proper eaiearea nee. s, 1964l n 5vention, that alkylation Vreactions carried out under conditions whichinclude adiabatic operation or temperatures which, although controlledto some degree, nevertheless fluctuate over a relatively wide range, donot result in high yields of high quality alkylate. The alkylationreaction between an alkylatable hydrocarbon and an olefin is carried outin the liquid phase at as high a temperature as liquid phase conditionswill permit so as to maintain a reasonable rate of reaction. However,the alkylation reaction is exothermic and, therefore, when alkylation iseffected quantities of heat are given off to raise the temperature ofthe reaction mixture. This effect is greatly magnified when alkylationis carried out in a series of reaction zones with continuous flow of thereactant mixture through the zones. It is known that as the alkylationtemperature increases, the formation of polymers which degrade the-alkylate product rises to a maximum. Therefore, a method of controllingternperature or removing heat from the exothermicalkylation reaction insuch a manner that a favorable rate of reaction is maintained is highlydesirable.

Prior art methods have `applied refrigerative cooling subsequent to thealkylation reaction in an attempt to provide some measure of temperaturecontrol. This is accomplished by providing an alternate series ofreaction and cooling zones. However, this method permits the temperatureat the point of reactant contact, viz., the point of olefinintroduction, to rise abruptly upon the spontaneous-reaction ofisoparaffin and olefin. This condition is extremely detrimental to thealkylation reaction since it is yat this point that a portion of theolefin reactant undergoes hydrosulfation and the amount of olefin whichenters into this side reaction, increases with the temperature.Therefore, prior art methods of refrgerative cooling, do not present asatisfactory solution to the problem of temperature control.

To reduce the residence time of reactants in a particular zone,pressured feed streams have been recommended to force the volume ofliquid through the reaction zones at a faster r-ate. However, thismethod has been found to be impractical since iiooding of the zonesresults and the cost of the resulting high circulation rates isprohibitive.

It is, therefore, an object of the present invention to provide analkylation process which results in the maximum production of highquality alkylate.

Another object of this invention is to provide a process for thealkylation of an alkylatable hydrocarbon and an olefin with the minimumVformation of sulfate byproducts.

Another object of this invention is to provide a process for reacting analkylatable hydrocarbon with an olefin in a plurality of reaction zoneswherein the time intervals between alkylat-able hydrocarbon contact witholefin is reduced to `a minimum. Y l

Another object of this invention is to provide an alkylation processhaving improved pressure control.

Another object of this invention is to provide a method Y for obtaininga more favorable mole ratio of reactants at the point of reactantcontrol.

Another object of this invention is to provide an improved method ofpassing liquid reactants from one reaction zone to another. l

Another object of this invention is to provide a method for carrying outmulti-zone alkylationreactions in the absence of ooding in the zone andresistance offered by the specific' gravity differences of liquids. Y

Still another object of thisv invention is to provide a process foreffecting liquid phase alkylation of isoparain hydrocarbons with olefinhydrocarbons in the presence of an acid catalyst inwhich theacidcatalyst and the isoparaflin hydrocarbon reactants are progressed inseries flow through a plurality of reaction'zones, while the olefinhydrocarbon reactants lare supplied in parallel flow to the plurality ofreaction zones to be intimately intermixed thereat, substantially assupplied, with the isopara.-

fin hydrocarbon and the acid catalyst fiowing through the respectivereaction zones, the series flow of the isoparaflin hydrocarbon and theacid catalyst being from the bottom to the top of a respective zone andfrom thence to the bottom of the next zone, the mixing means beinglocated at the bottom of each of said zones so that no material can passthrough any one of said zones without passing through the respectivemixing means and traversing the full length of said Zones; said mixingmeans furthermore inducing a suiiiciently high flow rate in the regionof olefin hydrocarbon introduction to establish thereat a desired highisoparain hydrocarbon-olefin hydrocarbon ratio.

Still another object of this invention is to provide a process foreffecting liquid phase alkylation of isoparaffm hydrocarbons in whichthe acid catalyst and the isoparafiin hydrocarbon reactants areprogressed in series flow through a plurality of mixing and reactionzones, while the olefin hydrocarbon is supplied in parallel ow to eachof said zones; said mixing zones being separate and maintained atpressures sufficient for evaporation of hydrocarbon supplied to the feedfor auto-refrigeration of said reaction zones, said pressures beingadjusted and controlled to promote the flow of the materials throughsaid separate zones.

According to the process of this invention, an alkylatable hydrocarbonis reacted in the liquid phase with an olefin in a plurality of reactionzones Within a reactor under controlled pressure conditions such that aprogressively lower pressure is maintained in each succeeding zone inthe direction of liquid fiow through the reactor. The reaction ispreferably carried out under substantially isothermal conditions byvaporizing 10W boiling hydrocarbons yand removing at least a portion ofthe vapors to dispel the sensible heat of reaction given off at thepoint of olefin introduction into an alkylatable hydrocarbon-acidemulsion. The vapors produced in a given zone are confined therein and acontrolled amount of vapor from each of the reaction zones is withdrawnto maintain substantially a constant pressure in each reaction zone andestablish decreasing pressure along the liow path of the reactantmixture passing through cach of the succeeding reaction zones in thereactor. Thus, the flow of the reaction mixture, which is induced by therelative pressure dierential between zones, is conducted through thezones in series at a high rate of circulation Vand in the absence of theoccurrence of ooding within the zones. This result is accomplished witha relatively low reactant feed rate to the reactor.

Also, by the present process, the sensible heat of the exothermicreaction can be removed during the reaction, or as soon as it isgenerated by spontaneous vaporization to provide improved temperaturecontrol as under isothermal conditions in the reaction zone or in theentire reactor, if desired.

The alkylatable hydrocarbons which are referred to in the process of thepresent invention are aromatic compounds, such as, for example benzeneand toluene, and aliphatic compounds. Among the specific aliphaticcompounds contemplated within the scope of this invention are isobutane,isopentane, etc. The olefin reactants included in the scope of thisinvention comprise ethylene,

ropylene, butylene, etc., and isomers thereof.

The temperature and pressure at which the overall ailrylation reactionsare carried out is within the range of between about 5 F. and about 159F. and from about 0 p.s.i.g. to about 100 p.s.i.g. for aliphaticalkylations and somewhat higher for aromatic alkylations. For example,in the alkylation of benzene with propylene, a ternperature of betweenabout 350 F. and about 480 F. under from about 500 p.'s.i.g. to'about 7G0 p.s.i.g. is generally employed. As stated above, to maintain a highreaction rate, the alkylation temperature Vfor a given system ispreferably at a temperature as high as liquid phase reacting conditionswill permit. For convenience, the followdiedero ing Table I recites theboiling points at atmospheric pressure of various components which maybe present in the reaction'mixture.

TABLE l Boiling Points of Reactiony Components at A tmospherc PressureOrganic Chemist-ry, R. Q. Brewster, Second Edition May 1953.

The alltyiatable hydrocarbon at the point of contact with oleiin isalways excess and preterably in a mole excess of at least 200, althoughhigher mole ratios of allrylatable hydrocarbon to olefin, in the orderoi about 400:1 or higher, are most preferred.

The high molar excess of alkylatable hydrocarbon is maintained at thepoint of oleiin introduction in various ways in accordance with thepresent invention. For examle, the circulation rate or" isoparailin pastthe point of olei'in introduction can be increased to such anextent'that the mole ratio in the respective feeds is multiplied by afactor of about However, this method does not supply an excess ofisoparaiiin within the above preferred range, namely, a molar excess inthe order of between about 200:1 and about 400: 1 or higher. Also, therequirement load on the impeller necessary to provide an isoparainexcess within this range is unfavorable from an economic viewpoint.Thus, 'the method of maintaining a higher molar excess of isoparatiln bythe process of the present invention is to employ an impeller mixingdevice which, after passage oi the alkylatable hydrocarbon past thepoint of olefin introduction, provides means for recirculating at a highvelocity the unreacted mixture to the mouth of the mixer forrecirculation therethrough.

The mixing means employed in the reaction zones are preferably enclosedby a hollow shell and have greater capacity than required to handle theacid and reactants applied to the respective zones so that recirculationof materials in the respective zones takes place. Since the zonescontain materials ofdiderent densities, stratilication can and does takeplace. When positive mixing and turbulence is discontinued ythesemi-quiescence required for stratification is provided, preferably byallowing the reaction mixture, after olein introduction to rise inelongated product taire-oil tubes located within the hollow mixer shell.The vapor, which then forms an upper layer within the shell is dispelledfrom the upper portion thereof, wl'dle the liquid'is allowed to overflowthe tubes and is expelled from a lower portion ofthe mixer shell. Ofcourse, it is to be understood that other means of accomplishingstratication may be employed, if desired; for example, coalescinginduced bya demis'ter pad. etc.

Provision is made for retaining the lighter material in.

the upper portion of the reaction Vzone away from the inletV of themixing means so that the body of liquid,

and the next succeeding zone, although the pressure drop betweenadjacent zones within the reactor need not be uniform.

In regard to the contacting of isoparahin with olelin, it is alsoadvantageous to circulate isoparatlin-acid emulsion past the point ofolefin introductionV at a rate of between about 8000 gal/min. and about15,000 gal/min. Since the acid catalyzes the alkylation reaction, itserves to best advantage in the form of tiny droplets in the alkylatablehydrocarbon phase and, when a uniform distribution of acid inalkylatable hydrocarbon is maintained, the side reaction ofhydrosulfation is greatly reduced.

In general, the present process comprises supplying olefin in aplurality of separate parallel streams to a plurality of reaction zones,supplying catalyst and alkyl-A atable hydrocarbon in the form ofalkylatable hydrocarbon-acid catalyst emulsion, to the first reactionzone for series ilow through each of the succeeding zones, passing theemulsion upwardly in a mixing device enclosed by a hollow mixer shellpast the point of olen introduction whereupon a portion of the mixtureis spontaneously vaporiaed as a result of the exothermic reaction,removing sensible heat of reaction by withdrawing vapors from the hollowshell and a controlled amount of vapor from the reaction zone tomaintain a predetermined pressure, preferably a constant pressuretherein, while recirculating at least a portion of the liquid reactionmixture to the mouth of the mixer for recontact with olen, maintainingthe liquid in said zone at a predetermined level by inducing the flow ofliquid by suction over a liquid level establishing means, into a take-odconduit which terminates at the bottom of the next succeeding zonemaintained at a lower pressure than the previous zone from which theliquid is being expelled and repeating the above procedure in each ofthe succeeding reaction Zones.

As explained above, the pressures in each ofthe plurality of reactionzones decreases in the direction of ilow of the reaction mixture, thusinducing the flow of reaction mixture from zone to zone, in series at ahigh rate. The pressure drop from one zone to the next is between about0.5 psi. and about 10 psi., and preferably between about l psi. andabout 3 psi. In the alkylation of-an isobutene with an olen, thepressure drop between zones is most preferably maintained at betweenabout 1.4 p.s.i. and about 2.6 psi.

According to this invention, a relationship was observed which enablesthe pressure diii'erential between any two zones to be determined in anymulti-zone liquid phase operation wherein the reaction zones arearranged side by side as in a horizontal reactor or one on top of theother as ina vertical reactor. The following formula was developed forthe purposes of the present invent-ion.

(de(he) df(hf) 2.31 Y lwherein P1 is the pressure in a reaction zoneexpressed in pounds per square inch; P2 is the pressure in the nextsucceeding reaction Zone; de isthe average specific gravity of theemulsion in reaction zone of P2 pressurej he is the liquid level, infeet, o-the liquid in reaction Zone of P2 pressure; df is the specicgravity of the liquid flowing from reaction zone of P1 pressure to thereaction zone of P2 pressure; Vhf 'is the liquid level, in feet, of theliquid being transported into the zone of P2 pressure and F is thefrictional loss during transportation expressed as Vpounds perV squareinch. Specifically, in a cascade reactor, for example, the cascadereactor shown-inthe accompanying drawing, lzfis the liquid level in thepassage',- way connecting the reaction zones, e,g. passageway 28. On theother hand, in a'vertic'al reactor, where the reaction `zones aresuperimposed on one another, hf thef'difference between hf and J1,2would be the height, in feet, f

a high density because of its emul-siiication with acid;

therefore, the liquid in the lower portion of the reaction zones is ofhigh density. However, as the liquid level rises in the reaction zone,the density of the liquid above the liquid exit ports in the mixer has alower density due to partial disintegration of the emulsionand,therefore, the liquid overliowing the level establishing means is at alower density than the liquid in the bottom of the zone to which it isbeing conducted.

By carrying out alkylation according to the .above process, theresidence time of the reaction mixture in a given reaction zone ismarkedly reduced, conditions in a reaction zone are maintained at aconstant temperature so that the reaction in the zone can be conductedunder completely isothermal conditions, and the isothermal operation canbe extended over the entire alkylation reactor, if desired, byregulating the amount `of vapor removed in each zone. Y

For optimum efficiency of the above process, it is also advantageous tointroduce allrylatable'hydrocarbon and acid catalyst to an admissionchamber prior to entry into the first reaction zone. ln the admissionzone certain low boiling components of the dkylation feed, for example,methane and ethane, when present therein, are vaporized and removedimmediately from the reactant mixture. Since these low boilingmaterials, if present, may cause diiculties in later stages of thealkylation reaction, such as, for example, causing vapor-locking in themixer and in the conduits connecting the reactions, they are preferablyremoved prior to reaction in the admission zone. This vapor and theremaining vapor, which is formed by the exothermic reaction and which iswithdrawn from the various reaction zones as a means of pressure and/ ortemperature control, is preferably reintroduced into the reactor in theproduct separation section, after which the vapors are withdrawn,cooled, concentrated in higher boiling components, and the higherboiling components returned to the reactor in the feed thereto.

The invention will be particularly described with reference to theaccompanying drawing which illustrates the process by reference toembodiments of a preferred apparatus -in which the invention is carriedout. It is to be understood, however, the invention yis not limited byrer"- erence to the specific modifications illustrated by the drawing,but is capable of other modiiication within the scope of the invention.

In the drawing,

FIGURE 1 is a side View illustrating a suitable apparatus in which theprocess of the invention is carried out; and

FlGURE 2 is a diagrammatic View of the process steps in apparatus set upfor carrying out the novel process of the invention.

Referring to FGURE 1, the reactor 1@ may be of any convenient shape andsize but is preferably in the form of a closed ended cylindrical orapproximately cylindrical tank as shown. The reactor 11i-is divided bymeans of a bathe or dedector plate 13 and partition 31 into a reactionsection 11 and a separation or settling section 12. The reaction section11 is conveniently of approximately the same volume as the settlingsection 12 but this ratio is subject to wide variation. Y

The reactionsection 11 is divided into an entrance zone 14 and aplurality of reaction zones, three reaction zones 15, 16 and 17 beingincluded -in the'- reactor 1d yshown but two, or more than three, may beemployed as operating conditions require. The entrance zone 14 is atonel end of the reactor 1@ and is detined by the dishedv head 18 and thecircular partitionk19. The partition 19 has a bottom section thereofremoved to provide a port 2t) through which materialin the zone 14 maypass for entrance into the bottom ofthe reaction/zone 15. Reaction zoneis deiined by the cylindrical walls of the reactor 1t) and has one endclosed by the partition 19 and the other end by the partition 19(11).The Weir or liquid levelfestablishing' means 22 provided adjacent thepartition 19(11) is circularfbut has `a .muchY largerV section removedfrom Iits top and is arranged to form a of the partition 1? and itssides united to the cylindricd wall of the reactor 1t), as by welding,to provide a passageway 26 for flow of material from the bottom of theentrance zone 14 to substantially the middle region of the bottom of thereaction zone 15. A small plate 27 is united to thewalls of the reactor19 and to the end of the rectangular plate 24 to close the end of thepassageway 25 so that all the material that enters the port 2@ can onlypass -into the reaction zone 15 through the hole 25. if deemed necessarya small hole, not shown, may be drilled through the plate 27 adjacentthe bottom lthereof for drainage purposes, otherwise no holes or portsare provided in any of the partition members mention.

The construction of reaction zone 15 is substantially identical to thatof zone 15, the corresponding parts of the zone 1o are designated byidentical numerals followed by the letter (a), except in the case ofpartition 19 which is followed by the letter (b). The material from thereaction zone 15 overflows the top edge of the partition 2.2, then flowsdown through the downtlow passageway 2S, formed between the partitions22 and 19(62) to enter the port 290.2). The reaction zone 17 is similarto the zone 15 and the corresponding parts thereof have been designatedby the identical numerals followed by the letter (b). The reaction zone17 or the final reaction zone, ditiers from the reaction zones 15 and 16or preceding reaction zones primarily in that the downstream end thereofis defined by the coalescer partition 31 and the deilector plate 13 andin that it is in open communication at its top with the settling section12.

The detlector plate 13 is united to the walls of the reactor 16 andextends from the coalescer 29, dened by partitions 31 and 32, to a levelconsiderably above the top ofthe partitions 22 and 22(51) and across thetop of the liquid settling zone o5 to the top of the settling section 12on the downstream side of vapor take-oli nozzle 59 so that all of theliquid material that passes from the reaction section 11 to the settlingsection 12 must pass through the coalescer 29 and any liquid entrainedinA vapors leaving reactor 1G by means of take-off nozzle 69 is returnedto the settling section by nozzle '70 arid conducted .to the coalescer29 wherein the separated liquid is admixed with the liquid productmixture from reaction zone 17. If desired, the detiector plate 13, shownin the drawing, can be replaced with a dedector of the type shown incopending application Serial No. 387,118, which comprises a plateextending above the partitions 22 and 2201) to a level somewhat belowthe top of settling section 12. The space between the partitions 31 and32 is filled with a suitable packing 33 such as carbon Raschig rings, orcrushed siliceous rock or ot er suitable material which is inert to thereactants. The partition 31, which is solid, is substantially the sameas and corresponds to the weil' partitions 22 and .22(a) and establishesthe liquid level in the `reaction zone 17. The partition 32 isperforated to permit liquid flow therethrough.

Each of the reaction zones 15, 15 and 17 has a mixer or mixing zoneprovided therein. The mixers 35, 35(a) and 35(1'2) are identical inconstruction so that the description of one of them, the mixer 35, willsufce for all. The mixer 35 is mounted in'a circular opening 36 formedin the top ofthe zone 15 and with its lower inlet end spaced from theplate 24 and overlying the hole 25 therein, The hole 25 is smaller thanthe inlet of the mixer 35 and the relative areas of the inlet of themixer 35 and the hole 25 andthe spacing of said inlet from the plate 24areA so proportioned and adjusted that all thev materials iedere Qsupplied to the hole 25 enterssaid inlet while permitting entrance ofdesired quantities of additional material through the space between thehole Z and said inlet. To this end also, the hole may have an' upwardlyextending rim or lip united to its periphery (not shown).

The walls of the opening 3-5 areV built up to form a liange ofappropriate size to support the mixer while in operation. The mixer 35is suspended from an annular iiange ring 3S whose outer peripheralportion rests on the face or the flange and is fastened thereto by aseries of bolts. Extending downward from the flange ring 33 an fastenedrigidly thereto, as for instance by a series of bolts, is a cylindricalshell 3?. rEhe shell 39 extends downwardly into the mixing zone l5 asubstantial distance and is closed at its lower end by an annular tubesheet 4b which carries a series of elongated talee-oli` tubes extendingupwardly therefrom (not shown).

An impeller housing 42 is positioned beneath the tube sheet 46. Theshell 39, the tube sheet 4S and the impeller housing 4f. are fastenedtogether into a um't by means of a series of studs which enter tappedholes in a ilange at the lower end of the shell 39 and carry suitablenuts threaded thereon which bear against a iiange forined at theperiphery of the irnpeller housing 42.

The mixer, indicated in FIGURE l by numeral 3S is more fully describedin FGURES 4 and 5 of copending parent application Serial No. 387,118,now US. Patent No. 2,927,009. The mixer described in application SerialNo. 501,292, now U.S. Patent No. 2,920,124, can be substituted for themixer employed in FIGURE 1, if so desired, and many other modificationsand changes can be made in regard to the mixer without departing fromthe scope of this invention. Generally, the internal structure of therrixer comprises in the venturi-shaped throat of the impeller housing42, an impeller blade, vertically elongated vanes above the impellerblade and ole-iin in troductiou means or ports above the vanes to whicholefin is supplied by pipe 51. A centrally located drive shaft, enclosedby a drive shaft housing, traverses the entire mixer shell and housingand is attached at the lower end to the impeller and at the upper end isconnec-ted to driving means 5b. The portion of the shell 39 extendingupward from tube sheet it? contains a plurality of elongated producttake-oli tubes distributed circumferentiall extending paralleltherewith.

The' open upper end of each of said elongated tubes terminates asubstantial distance below the flange ring 38' sothat sufficient spaceis provided within the shell 'for the separation of vapor in the upperportion of he shell, withdrawing of these vapors from the mixer by meansof ports43 and reversing the direction of ow or the liquid materialpropelled through the tubes by the' impeller.

After the flow reversal just mentioned, the liquid material liowsdownwardly in the space between the elongated` tubes, the drive shafthousing and shell 39 to exit from the series of elongated openings 53located adjacent the lower end of the shell 39'. vapor vent rneans43'are provided adjacent the upper end ot the shell 39 above theterminus of the elongated take-V .tition Si? is at a somewhat hig .erlevel than thel top edge oi the opposed perforated plate 32 of thecoalesc'er 29. The liquid reaction material as it passes through the co-A series of comparatively small" around said drive shaft housing and yproduct zone 6l while the acid settles in the bottom of the acid zone62. IThe liquid hydrocarbon product is removed through the pipe nozzle63 in the bottom of the liquid product zone 6l for further processing.The acid is removed through the pipe nozzle 64 in the bottom oi theliquid acid zone d2.

The zones i5, 16 and i7 are each provided with a nozzle 66 to facilitatethe removal of residual material `from the respective sections duringcleaning, etc. The zone 14 is provided with a nozzle 67 through whichthe isoparatln hydrocarbon or isoparaiiin` hydrocarbon in admixture withacid catalyst may be introduced into reactor lil. Zone 1S includes anozzle 71 through which acid catalyst is supplied to the'reactor 1l) andmixer 35 when not supplied in admixture with insoparain or to supplementthe volume of acid introduced Vin admixture with isoparaiiin in nozzle67. Zone l. as well as zones l5 and lo are each provided with a nozzler,63 (a) and 68(5) respectively. The nozzles 5S, 68(11) and 68(15) may bemanifolded through suitably valved lines, as shown for instance inFGURE. 2, so that vapors can be withdrawn from zones i4, 15-and le atcontrolled rates and then passed into section l2 by means of nozzle 68(c) By suitable control of the gas ilow out of zones 14, i5 and 16,these zones may be maintained under any preferred pressure arrangement,however, the' pressures in the zones l., it and 16 should progressivelydiminish but all must always be higher than the pressure in zone 17 soVthat the pressure diderential will be elective to facilitate the seriestlow of the reactants through the zones id, 1S, lo and i7 andparticularly so that the light reactants will liow in the acid catalystor the emulsion phase in the succeeding zone.

The section l2' includes the nozzle 69 for conducting gas from saidsection, as for instance to a compressor .of a retri'ge'rating system.The section 12 furthermore 1ncludcs a nozzle itl through which may bereturned to the settling section if, any liquid material, particularlyany acid, carried out by the gas stream issuing from the nozzle 691 Whenemploying the deector plate shown in Serial No. 387,118, a pipe extendsfrom the nozzle 7b to assure the return ci the material to the acidsection l2 and beneath the liquid level therein'.

The reactor i0 may be variously modiiied without departing from theinvention. Thus, in place of the speciiic type of reaction zones,reaction zones each including two or Vr'n'ore mixing zones and asettling section,- may be disposedl on each rside of a single productzone and all three zones included in a single vessel.

ln carrying out' liquid phase reactions in a plurality of reactionzones, in the presence of a liquid catalyst which is irnrniscibie withthe' alkylatable hydrocarbon, as for instance in the alkylation ofisoparaiiin hydrocarbons in which sulfuric acid is employed as thecatalyst, and in accordance with the process oft e present invention,reference is had to FGUR'E Zot the drawing. Using the reactor lilabovedescribed, the isoparafn hydrocarbon feed which comprises theisoparain hydrocarbon recycle feed and any fresh isoparafn hydrocarbonfreed required andl not supplied by the a'lkyla'tingA hydrocarbon feed,after having thefrecycle acid catalyst added to it is introduced inadrnixture with recycle acid catalyst, hereinafter described, into the.entrance zone ill throughthe nozzle di",A from line lili) While thefreshV acid catalyst.

feed is introduced into the bottom or zone 15 and be-l neath the hole 25through the nozzle 71 from line 192.

` The isoparafiin hydrocarbonV feed may comprise a single alescer 29separates into acid and liquid hydrocarbon and layer separation of thetwo takes place in the acid zone 62.. Thel lichter'licpiidV hydrocarbonbeing the' top layer, overilows partition 3d and collects in the liquidisoparaliin hydrocarbon or a'- mixture of such hydrocaq bons' or amixture comprising oneor more isoparain hydroca'rbons and one or morenormal paraiiin hydrocarbons. The mole ratio of isoparaliin to totalacid which enters mixer 35 is generally in the order of between aboutAlternately the zone 14 may be eliminated and the isoparafiinhydrocarbon feed as defined above and without the addition of the acidcatalyst recycle, supplied directly to the inlet of the mixer 35 throughthe nozzle connection 71 while the recycle acid catalyst and the freshacid catalyst after being joined are supplied to the bottom of the zonethrough the nozzle 66. It is also possible, though not preferable, whenthe zone 14 is eliminated, to locate the nozzle 67 on the axis of themixer 35 and the nozzle 71 adjacent thereto and beneath the hole 25 sothat the isoparafn and the acid catalyst enter the reactor 10 atsubstantially the same location at the bottom entrance to the reactionzone 15.

The alkylating hydrocarbon feed which may be a single olefinhydrocarbon, or a mixture of olefin hydrocarbons, or a mixture of one ormore olefin hydrocarbons and one or more isoparafiin hydrocarbons whichmay also include one or more normal paraffin hydrocarbons is dividedinto separate parallel streams and a separate stream enters each of themixers, in FiGURl-. 2, mixers 35, 3501) and (b) through the respectivenozzles 51, 51(a) and 51(1)) from lines 194 to lit). It is to beunderstood, however, that a greater number of reaction zones, and thuscorrespondently a greater number of mixers and streams of olefin arepreferred in carrying out the process of this invention.

The isoparaflin hydrocarbon content of the alkylating hydrocarbon feedmay be less than, or equal to, or more than the quantity required forallcylation reaction with all of the olefin hydrocarbon present.However, in the case of isobutane alkylation, the isobutane content ofthe olefin feed usually approximates that required to react with all ofthe olefin hydrocarbons present. Thus, the isobutane feed is largely arecycle feed and is. provided in such quantity as to maintain thepre-established isobutane to olefin feed ratio, for example, in theorder of 10:1 in individual reaction zones. In accordance with thepresent invention, isobutane to olefin ratios in the order of 8:1 forthe individual reaction zones and in the order of 3:1 for the wholereactor 10 are preferred, although, at the point of contact of olefinwith isobutane at least 150:1 can be obtained. Isoparaffimoiefin ratiosas low as 150:1 will provide important improvements in results, but bestresults are obtained with ratios in the order of 400:1 and higher at thepoint which olefin is j introduced and contacted with the isoparafiinacid emulsion. Y The alkylating hydrocarbon feed introduced into thenozzle 51 will ow downward through the drive shaft housing to exit outof the ports or olefinintroduction means at the outlet of the impellerand vanes of mixer 35 to be admixed thereat with the acid catalyst andisohydrocarbon feed pumpedrby the impeller blades upwardly at maximumvelocity past the point of olefin introduction. The impeller is operatedat relatively high speeds in a manner to impart high velocityv to theliquid presented to it so that it rapidly and intimately intermixes theacid catalyst, the isohydrocarbon, and the lallrylating hydrocarbon andforms therefrom an emulsion. The emulsion is further formed ormaintained Vby the flow thereof through the elongated product take-offtubes above the point of olefin introduction, by the rapid reverse indirection of liquid flow in the space above the outlet of these tubes.and the flow through the comparatively restricted passages between thetubes, the interior of shell 39 and the exterior of the drive shafthousing before the liquid is expelled from the mixer through ventingmeans 53 The flow of the emulsion at high velocity and inthe mannerdescribed, produces shearing eects whereby the droplets of theemulsion,which ordinarily contain the isoparaffin reactants, are'continuouslysubdivided to present Y new surfaces for reaction and to present a largearea of A presentation of fresh isoparafiin reactants at the surfaces ofthe droplets, which is the location at which reaction occurs.

The procedure of mixing the catalyst and reactants and reacting theisoparaiiin and olen in zone 15, is repeated in zones 16 and 17 inmixing zones 35(a) and ftb) as the liquid emulsion passes seriallytherethrough. The capacity of the impellers of mixers 35, 35M) and 35(b)is greatly in excess of that required merely to pump the acid catalyst,the isohydrocarbon and the alkylating hydrocarbon supplied through thenozzles 71 and 67 and the olefin introduction means respectively throughits respective mixing section so that a rapid recirculation of theemulsion within its respective mixing section takes place and the mixers35, 3501) and (1)) are positioned sufficiently above the respectiveplates 24, 24M) and 24(15) to facilitate the recirculation of liquidexpelled from the respective apertures 53, 53(a) and 53(b) to theimpeller in admixture with liquid entering the respective mixer fromhole 25, 25(a) and 25(b). The capacity of each of the mixers 35, 35(a)and 35(b) is such that material presented to each of them isrecirculated from about 10 to about 40 times, preferably 15, or moretimes before it leaves the respective reaction zone 15, 16, or 17. Therapid recirculation of unreacted liquid material through the mixers andpast the point of olefin introduction provides much shorter intervalsbetween isoparaffin-olefin contact as compared with prior methods inwhich the isoparafdn is contacted with olefin only once in eachparticular reaction zone and in which it is necessary to circulate theentire liquid mixture to succeeding reaction zones for each contact witholefin. The longer the interval between olefin contact, the greater theformation of undesirable by-products due to hydrosulfation.

Since each impeller is arranged to recirculate the acid catalyst and theisoparaiiin content of its respective mixing section many times past theolefin introduction ports through which the olefin reactants aresupplied, this results in effect in multiplying the ratio of isoparafnhydrocarbon to olefin hydrocarbon many times. Thus, if the ratio ofisoparaflin hydrocarbon to olefin hydrocarbon supplied to the reactor 1@is in the order of about 4:1, the ratio for each mixing section will beabout 10:1. If each impeller recirculates the content of its respectivemixing chamber l5 to 40 times, as in the preferred operation of thepresent invention, the mentioned ratio is increased to the order of to400 to l and lthe quantity or" objectionable compounds formed by thehydrosulfation is reduced to a minimum. The olefin hydrocarbons are thusimmediately upon introduction into the reaction zone, subjected tooptimum conditions for promoting alkylation reaction with a minimumformation of the objectionable lay-products thereof.

` By maintaining a proper pressure relation between the zones 14.1, 15,16 and 17, the emulsion Voverfiows the bafile 22 in zone 15 to flowdownward through the passageway 28 and through the hole 25(a) and to bepresented to the mixer 35(a) at a rate substantially in excess of thecombined rate of acid catalyst and hydrocarbon input. The mixing andrecirculation action discussed above is repeated in reaction zone 16 butwith'the admixture of a fresh supply of alkylation hydrocarbon orolefin, and again emulsion flows yover the weir 22(a) to the hole 250;)Yfrom passageway 28(a) and to the bottom of the reaction zone 1'7 at arate substantially in excess of the combined rate of the acid catalystand hydrocarbon input. In the reaction zone i7, the mixing andcirculating action-is again repeated and again with admixture of a freshsupply of alkylating hydrocarbon.

The reaction zone 17 is in open communication with the vapor sectionrdiand at the same pressure as the settling section. 12, hence flow ofmaterial from the reaction zone 17V to the acid zone 62 does not'takeplace because of a difference in static pressure but rather be- 13 Ycause of dilerent pressure heads'. To this end, acid catalyst andproduct are drawn oh through nozzles ofi, line 112 and nozzle 63,1l1'ne114 respectively, at such rates as to maintain the liquid level in theproduct zone 6i below the liquid level in the acid zone 62 and' theliquid level in the acid zone 62 below the emulsion level in thereaction zone 17. Irdesired, the top of the deilector baiile 13 need notbe' attached to the top of reactor but can be positioned at such a levelas to prevent normal as well as accidental llow'o the Vemulsion in thereaction zone 17 thereovcr as shown in copending application Serial No.387,118. Delector baffle 13, as arranged in the accompanying figures ofthis application, not only serves to' prevent the emulsion in zone 17from by-passing the coaiescer 29, but also provides an ellicient meansfor returning liquid, entraine-.d with vapors, to the coalescer andtheliquid settling zone.

The emulsion leaves the reaction zone 17 over thetop of the weirpartition 3'1" andl flows through the coalescer 29 for flow into theacid settling zone 62 yor" the settling section 12. In owing through thecoalescer 29, the emulsion is broken down into two continuous phases. lnthe `acid settling zone 62 the lighter hydrocarbontseparates as a layeron the heavier acid catalyst to overflow the partition 39 into theproduct Zone 61 whcrcl'rom it is wimdrawn through the nozzle 63 forfurther processing and refining. he acid which collects in the bottom ofthe section 62 is withdrawn in part for recirculation and in part forreconditioning. The acid recycled to the reactor is passed in line 112to line 10d wherein it is mixed with incoming isoparaiiin. A valvedbleed-olf line 116 is provided in line 112 to removeV a portion of thespent acid from the system. Fresh acid is addedV to the system throughline 192 at a sufficient rate to maintain the required catalyst activityand usually corresponds to the amount of catalyst withcu'awfn from thesystem.

The reaction described is exothermic andl in order to maintain thedesired temperature, or a temperature with a desired range', the zones14, 15, 16 and 17 and section 12 must beV cooled. The heat of thealltylation reaction and the heat developed in the mixing operationnecessitates some means for cooling the reaction zone to maintain thereaction temperature at the desired level. Heat may be extracted fromthe body of liquids in the reaction zone by indirect heat exchange withan external refrigerating means. Vreferably, however, internalrerigeration is eiected by permitting cont-inuouspevaporation ofunreacted hydrocarbons' which are Withdrawn from the mixing sections,condensed, cooled, and returned for :further treatment. The necessarycooling effect may be obtained in various ways as by employing variousdevices, such as coils through which a cooling medium is circulated,etc. However, the process ofthe present invention preferably employsautolrefrigeration by evaporative cooling since this method possessesmany unexpected advantages over other cooling methods. For example, ashereinbeforel pointed out, spontaneous-vaporization provides immediatecooling at the point where the'reaction' takes place so that thetemperature ofV the/reaction can be more closely controlled and, foroptimum results, can be carried out under isothermal conditions. Thus',the isohydrocarbon feed and lowerV lboiling hydrocarbons inthe -feed arevaporized in the various zones-'mentioned atsuicient rates at theYoperating pressures to provide an essentially constant predeterminedtemperature, i.e.,- when operating under preferred conditions, tomaintain isothermal conditions in the reactor.

When the apparatus and process of the invention areV employed incarrying out exothermic reactions in which the heatfdeveloped causesvaporization of a portion of the liquid reactants during the process,they method of' introducing the alkylating hydrocarbon -feedV to themixers 35, 35(11) and 35(1)) is particularly advantageous. For example,in the alkylation ofV isopar'ain hydrocarbons with olefinhydrocarbonsunder conditions of temperature; and pressure permittingcontinuous vaporization of unreacted hydrocarbons for temperaturecontrol purposes, it is particularly advantageous to introduce the olenreactants at the outlet or high pressure side of the impeller. In viewof the relatively low concentration of oleiins maintained in the reactor10 as a whole, it is evident that the alkylation reaction, and thedevelopment of exothermic heat of reaction, are most intense at thepoint where the olefin reactants are admixed? with the `isoparaiiins andthe acid catalyst. The spontaneous vaporization of a portion of themixture at that point, therefore, is relatively high. Consequently, theintroduction of olelin feed through ports in the oleiin introductionmeans into the high lpressure side of the impeller has the advantage ofpermitting vaporization without intertering with circulation. Theintroduction of the fresh feed in this manner also accomplishessubstantially instantaneous and complete mixing of the olen reactantswith the acid and the isopar'ailins discharged I.from the impeller andthe Vresulting mixture is then immediately driven through the producttake-oli tubes to promote further v intimate and effective contact ofreactants and catalyst.

As discussed above, the isopralin feed usually contains quantities ofhigher and lower boiling materials, thus, isobutane, available forchargematerial to an alkylation process, ordinarily occurs in mixtures whichcontain v substantial quantities of normal butane and propane and may ormay not contain minor quantities o f ethane and/or methane. inasmuch asmethane, ethane and propane, together with isobutane, constitute thelowest boiling constituents in this portion of the reaction mixture,refrigeration by evaporation results in the separation from the reactionmixture of vaporized hydrocarbons comprising at least isobutane andpropane and predominating in isobutane. A controlled amount of thesevapors is Withdrawn, by means of valved lines 118, 12@ and 122 from each`of their respective entrance and reaction zones 14, 15 and 16 exceptfrom the iinal reactionrzone 17. The amount of vapor Withdrawn isindependently controlled' by valves for each zone and is dependent uponthe predetermined pressure pattern to be established and maintained inthe zones. From the respective withdrawal line, the vapors are passedthrough line 124., into vapor section 41 of settling section 12 by meansof line 126 and then into accumulatorV 13) by line128. Y are removedfrom the accumulator by line 132 and passed to the refrigerative systemwhich comprises: compressing the vapors in compressor 134, condensingthe compressed vapors by indirect heat exchange in cooler 136 andtransporting the condensed liquid to holding drum 138, after which a`least a portion of the liquid' is passed to a distillation zone or inthis instance a depropanizer by means of line 149. FollowingVdistillation or depropanization, theresult-ing liquid stream is returnedto entrance section 14 of the reactor 10' by means of recycle lines 142and 16%); The remaining liquid portion (if any)l from holding drum 138is directly recycledV to entrance section Vlll of the reactor by meansofrlines 140, 146, 1412 and 10d as `part of the isobutane Lfeedth'eretoAnyaddirtional is'par'an required foi" the operation of the presentprcessV is introduced'b'y m'eaismof line 147. t'is to 'beunde's't'ooi ofcourse; thatY otherV convenient treatments of theY vapbroiis' eiiieht"can be substituted for the treatment" abovelde'scibedl Forexai'n'ple',the' arrangementdescribed in U.S."Patent,2,829,l81 can be employed, ifdesired.

Accumulator may contain a coalescer 4or otherV suitable means forseparating any "liquid which hasbeen entrained withV the vapors removedfrom sectiongdl and any liquid separated therein is' returned, bymean-slof line 144,' tothe reactor coalescing zone 29 for entrywithisection below the liquid levelV therein by means of a con duit las inthe process described in copending application The vapors' 3,1 aders;

Serial No. 387,118. It is also to be understood that other variations ofthe above technique for handling refrigerative vapors Will now beapparent without departing from the scope of this invention.

The stage at which propane is eliminated in the present process isparticularly advantageous because the mixture, after compressing `andcooling, has a higher concentration of propane than at any other stagein the process. Sufficient propane is thus eliminated to balance theamount introduced into the system as fresh feed. The quantity of propanemaintained in reaction section 11 may -be regulated to provide thedegree of evaporation necessary to abstract the heat of reaction at theconditions of temperature and pressure at which it is desired to conductthe reaction. In the alkylation of isobutane with butene in the presenceof sulfuric acid, the lighter constituents of the isobutane recycle feedvaporize in the sections 14, 15, 16 and 17 to cool the content oftherespective sections and to maintain a pre-established lowtemperature, most preferably about F. By adjustment of the valve meansin the piping through which the vapors ow out of the sections 14, 15 and16, desired pressures may be maintained in the respective mixingsections. Thus by Way ofexample, the valving may be set to maintain apressure of 8 p.s.i` in thesection 14, a pressure of 7 p.s.i. in thesection 15, a pressure of 6 p.s.i. in the section 16, and a pressure of5 p.s.i. in the section 17 and the settling zone 12. VThe diminishingpressure of the zones induces the tiow offliquid from one zone toanother at a high rate and obviates the diiculties associated withooding of the reaction zones.

. In FIGURE 2, the arrangements employed for preparation of the variousfeeds, the treatment of the acid catalyst and the treatment of theproduct have been omitted as such arrangements are largely conventionaland known in the art. For example, Patent 2,429,205 shows feedpreparation and product treatment arrangements suitable for use inconnection with the carrying out of the process of the presentinvention.

For a specific example of the operation of the apparatus and method ofthe invention, reference may be had to a specific use. In the specificuse, the alkylation installation described in FIGURES 1 and 2 was ofsuch a size that it produced 1690 barrels per day of alkylate product.For this quantity of product, the olefin feed employed was 3044 barrelsper day made up of Hydrocarbons- Barrels per day Ethane 4 Propylene 156Propane 504 Isobutane 1135 Butene 830 Normal butane -1 Pentane 14 Theisobutane recycle'was 9198 barrels per day' and made up of:

Hydrocarbons Barrels per day Ethane 3 Propane 841 Isobutane 7485 Normalbutane 852 Pentane 17 which 1690 barrels per day was alkylate productand 3599 barrels per day was unreacted material and contaminants.

The unreacted material was separated from the liquid mixture andreturned to the system as part of the isobutane recycle.

In operating in accordance with this specific example, the temperaturein the reactor was maintained at 35 F. To attain this constanttemperature, the valves in the vapor lines 118, and 122 from zones 14,15 and 16 were adjusted to maintain a pressure in the section 14 of 8p.s.i. differential, in the section 1S of 7 p.s.i., in the section 16 of6 p.s.i., and in section 17 and the settling section of 5 p.s.i. Tohandle the refrigeration load, 6553 barrels of liquid per day wereevaporated and removed from the settling section 12. The 6553 barrelsper day 'of condensed vapors were composed of:

The mixers 35, 35(a) and 35(b) were operated at such speed thatthe iiowtherethrough past the olefin feed inlet was such as to multiply theisobutane to olefin ratio approximately twenty-tive times so that theapparent isobutane to olefin ratio was increased to the order of about i200:1 at the point of contact. The time interval between olen contactwith a given portion of emulsion was reduced to 20 seconds as comparedwith an interval 4of about 5 minutes when recirculation within the zoneis not employed.

The superior results obtained by the use of the novel process of thisinvention is apparent from a consideration of the following comparativedata, column 1 being data derived from conventional practice, whereinthe pressure between reaction zones not controlled and the liquidreaction mixture is not recirculated through a mixing device, Whilecolumn 2 being data derived from practice in accordance with the presentinvention wherein a pressure drop of at least l p.s.i. is maintainedbetween the reaction zones and the liquidV reaction mixture isrecirculated through a mixing device as hereinbefore described.

Production (Barrels/Stream Day) 1, 211 1, 201 Space Velocityr (Volume ofAcid/Volume of Olctins/ Hr.) O. 30 0.302 l'sobntane in Reactor Etiluent(liquid volume percent) T 51.3 53. 1 External Isobutauc to Olcn Ratioper Mixing Section T 9. 0 9. 2a Internal Isobutane to Olen Ratio at2:1'Ac1d to Hydrocarbon Ratio 149 159 Residence time of Rcactants inReaction Section of Reactor (hours) 0. 6 O. 4 Pounds Acid Consumed/gal.Alkylatc Produced 1. 89 1. 35 Spent Acid Strength Nvt. Percent 94. 495.2 Rcruu Yield of 338 F. End Point Alkyato (Light n Alkylate) So. r91. Octane Number: T t IAM! 1 t Y 92 S v o a y a c. y FA Cleaimghliliyae. 93 2 n l{Tota i yac 1"2 C1-aftt.igiitaikyiate 91. s OctaneRating Performance Number: Y

F-3+4-6 cc. TEL Light ALlrylate 112 F-4+4.6 cc. TEL Light Alkylate V141In the above, F-l is equivalent to Research Octane Knock Rating; F-2 isequivalent to ASTM Motor Octane Knock Rating; F-3 is equivalent to LeanMixture Method Knock Rating for aviation gasolines; and F-4 isequivalent to Rich Mixture Method Knock .Ratings for aviation gasolines.i r

The above data shows that by the present process, acid consumption isgreatly reduced and hydrosulfation is reduced to a minimum as a resultof preventing all of thre liquid material leaving one reaction zone. toemulsiry and contact with olefin, a more favorable molar excess ofisobutane is obtainable without increasing the volume of isobutane feedand that these advantages result 1n a repeating the above procedure inthe second confine reaction zone; and separately withdrawinga controlledamount of vapors from each of the reaction zones to regulate thepressure therein so that the pressure in the first zone is maintained ata higher pressure than the second zone and so that the liquid ofrelatively low density 1n the second confined passageway from said firstzone 1s induced to fiow into liquid of relatively high density in thesecond zone in series at a high circulation rate.

5. The process of claim 4 wherein the alkylatable hydrocarbon comprisesan isoparafiin.

6. In an alkyl-ation reaction wherein an alkylatable hydrocarbon isreacted with an olefin in the presence of an acid catalyst, the methodwhich comprises: introducing an alkylatable hydrocarbon and an acidcatalyst into a multistage reactor containing a plurality of confinedreaction zones; passing the alkylatable hydrocarbon-acid mixture to thebottom of a first reaction zone through a confined passageway at a pointdirectly below an area of highest upward vertical velocity; emulsifyingthealkylatable hydroearbon-acid mixture; passing ,the emulsion upwardlyat a maximum velocity in a confined mixing zone, within the confinedreaction zone, past a point of olefin introduction under conditions suchthat the alkylation reaction takes place in the liquid phase andspontaneous Vaporization occurs; separating the vapors from theliquid toprovide a body of liquid with a superimposed body of vapor in the upperportion of the mixing zone and the reaction zone; permitting the liquidin the reaction zone to reach a predetermined level and to assume aminimum density in the upper portion of the liquid level; passing atleast a portion of the liquid in the mixingzone into said reaction zone,which liquid is of maximum density due to emulsification with acid;recirculating, at a high velocity, aportion of the liquid thus expelledto the area of highest upward vertical velocity and through said mixingzone for recontact with olefin; repeating the recirculation of liquidthrough the mixing zone between and 40 times before permitting saidliquid to leave said reaction zone; inducing the liquid to ow from saidreaction zone after reaching said predetermined level to the bottomportion of the next succeeding reaction zone, containing a confinedmixing zone, in a second confined passageway and preventing thecarryover of vapor to the next succeeding reaction zone; repeating theabove procedure in each of the succeeding confined reaction zones; andseparately withdrawing a controlled amount of vapors from each of thereaction zones to regulate the pressure there-in so that the pressure inthe first zone is maintained between about 0.5 -p.s.i. and about 10p.s.i. higher than the second zone to induce the .flow of liquid fromsaid first zone through the second zone in series.

7. Thel process of claim 5 wherein the pressure in the first zone ismaintained between about 1 p.s.i. and about 3 p.s.i. higher than thesecond` zone.

8. TheV process of claim 5 `wherein the alkylatable hydrocarboncomprises an isobutane.

9. The process of claim 5 wherein the olen comprises butene. Y Y

10. The process of claiml 5 wherein the acid catalyst is sulfuric acid.

1l. The process of claim 5 wherein the liquid mixture,`

after leaving the lastV reaction zonerin the series, is passed to acoalescing zone and thence into a settling zone for removal of catalystfrom the liquid product mixture.

Y 12. In an alkylation reaction wherein an alkylatable Vhydrocarbon isreacted with an alkylating agent in the presence of an immiscible liquidcatalyst in a confined mixing zone contained in a vconfined reactionzone the y process which comprises: passing the alkylatable hydrocarbonand the liquid catalyst to the lower portion of the reaction zone and toa confined space directly below an Varea of highest upward verticalvelocity,remulsifying the alkylatable hydrocarbon and the liquidcatalyst, passing the emulsion upwardly atV maximum Velocity within theconfined mixing zone past a point where the alkylating agent iscontinuously being introduced, under conditions such that thecondensation reaction between the alkylatable hydrocarbon and thealkylating agent taires place in the liquid phase and spontaneousvaporizatlon occurs, passing the resulting mixture in the nuxmg zoneupwardly through a semiquiescent zone to separate therefrom any vaporousmaterial, reversing the fiowbf the liquid mixture in a downwardlydirection within said mixing zone and expelling the liquid mixture fromthe confined mixing zone, recirculating a portion of the expelled liquidto said area of highest upward vertical Velocity 1n admixture with theincoming alkylatable hydrocarbon and catalyst and recirculating theexpelled liquid through the confined mixing zone for recontact with thealkylating agent.

13. In an alkylation reaction wherein an alkylatable hydrocarbon isreacted with an olefin in the presence of an imrniscible liquid catalystin a confined mixing zone contained within a confined reaction zone andwherein the sensible heat of reaction is withdrawn from said mixing zoneand said reaction zone by vaporizing a portion of the reaction mixtureduring contact, the process which comprises: passing the alkylatablehydrocarbon and the liquid catalyst to the lower portion of saidreaction zone and to a confined space directly below an area of highestupward vertical velocity provided by said mixing zone; emulsifying thealkylatable hydrocarbon and catalyst; passing the emulsion upwardly at amaximum velocity in the confined mixing zone past a point of olefinintroduction under conditions such that the condensation reaction takesplace in the liquid phase; passing the liquid reaction mixture upwardlythrough a. semiquiescent zone to separate therefrom Vaporous material;reversing the ow of the liquid mixture in a downwardly direction withinsaid mixing zone and expelling the liquid mixture from the confinedmixing zone; recirculating a portion of the expelled liquid to said areaof highest upward velocity in admixture with incoming alkylatablehydrocarbon and catalyst; recirculating the expelled liquid mixturethrough the confined mixing zone at high velocity for recontact witholefin reactant; repeating the recirculation of the expelled liquidmixture at least 10 times at high velocity to provide a mole ratio ofisoparafiin to olefin at the point of contact of at least :1 withoutaltering the volume of alkylatable hydrocarbon introduced to thereaction zone.

14. In an alkylation reaction wherein an alkylatable hydrocarbon isreacted with an olefin in the presence of an immiscible liquid catalystin a confined mixingzon contained within a conned reaction zone andwherein the' alkylatable hydrocarbon is introduced into the reactionzone in a mole ratio of between about 2: land about 20:1 alkylatablehydrocarbon to olefin, and wherein the serisible heat of reaction iswithdrawn from said mixing zone and said reaction zone by vaporizing aportion of the re action mixture during contact, the process which comeprises: passing the alkylatable hydrocarbon and the liquid catalyst tothe lower portion of said reaction one andto a confined space directlybelow an area of highest upward vertical velocity provided by said nnY'Xing zone; emulsifying the alkylatable hydrocarbon and catalyst;passing the emulsion upwardly at a maximum Velocity in .the confinedmixing zone past a point of olefin introduction under conditions suchthat the liquid phase condensation reaction'takes place; passing theliquid reaction Vmixture upwardly through a semiquiescent zone toseparate therefrom vaporous material; reversing the fiow of the liquidmixture in a downwardly direction within said mixing zone and expellingthe liquid mixture from the coufined mixing zone; recirculating aportion of the expelled liquid to said area' of highest upward velocityin admixture with incoming alkylatable hydrocarbon and catalyst;-

recirculating the expelled liquid mixturev through the conv fined mixingzone atl high velocity for recontact with:

Orem feactaat; rep-eating. are reclamation of the expelled liquidmixture at least times at high velocity to provide a mole ratio ofisoparathn to olen at the point of Contact of at least 150:1 withoutincreasing the volume of alkylatable hydrocarbon introduced to thereaction zone.

l5. In the ailiylation' of an alleylatable hydrocarbon with an olen inthe presence of a 1liquidV acid catalyst, the steps comprisingintroducing said alkylatable hydrocarbon and said liquid aid catalystitoa first reaction zone, intimately Said catalyst and alkylatablehydrocarbon in said reaction' zone to produce a body of alkylatablehydrocarbon-acid emulsion, introducing olens into said emulsion to eiectreaction of said olers with alkylatable hydrocarbon contained therein,owing a portion of said body of emulsion contained in said r'st reactionzone in a confined stream into a second reaction zone at a low pointtherein, intimately mixing said emulsion in said ecoud reaction zone tomaintain therein an alkylatable hydrocarbon-acid emulsion, introducingadditional olens into said second reaction Zone' .to eiect reactionthereof with al'kylatable hydrocarbon contained'ithe'rein, maintainingover the body of emulsion in each of said reaction Zones a separateconned vapor phase comprising hydrocarbon vapors evolved from theemulsion by the heat of reaction, separately withdrawing vapors fromeach of said vapor phases, and maintaining a higher` pressure on thevapor phase over the emulsion contained in said rst reaction zone thanthe pressure maintained on the vapor phase over the' emulsion containedin the second reaction zone to produce' a regulated flow of saidemulsion in said confined stream from said iirstreaction Zone to saidsecond reaction zone. u 1

16. In the alkylation of isoparaftn hydrocarbons with atenas in mepresence er a liquid acid catalyst, the steps comprising introducingsaid ispain hydrocarbons and said liquid acid catalyst into a jrs'treaction zone, intimately mixing said catalyst and hydrocarbons in saidreaction Zone to produce a body of hydrocarbon-acid emulsion,introducing oleiin into said emulsion to etect reaction of said olenwith isoparaiiin hydrocarbons contained therein, flowing a portion ofsaid body of emulsion contained in said nrst reaction zone in a confinedstream into a second reaction Zone at a low point therein, intimatelymixing said emulsion in said second reaction Zone to maintain therein ahydrocarbon-acid emulsion, introducing additional olein into said secondreaction zone to eiect reaction thereof with isoparafln hydrocarbonscontained therein, maintaining over the body of emulsion in each of saidreaction zones a separate conned vapor phase cornprising hydrocarbonvapors evolved from the emulsion by the heat of reaction, separatelywithdrawing vapors from each of said vapor phases and maintaining ahigher pressure on the vapor phase over the emulsion contained in saidirst reaction zone than the pressure maintained on the vapor phase overthe emulsion contained in the second reaction zone to produce aregulated flow of said emulsion in said conned stream from said rstreaction zone to said second reaction zone.

17. In an alkylation reaction wherein an alkylatable hydrocmbon isreacted with an oleiin in the presence of an acid catalyst, and whereinthe alkylatable hydrocarbon and acid catalyst are emulsied and passedfor series iiow throughV a multi-stage reactor containing a plurality ofconfined reaction zones with separate oleiin introduction into each ofsaid zones for contact with the emulsion, the improved process'fortransferring a liquid mixture comprising alkylatable hydrocarbon andacid catalyst at a relatively low density iirom one reaction zone into asucceeding reaction zone containing liquid of relatively high density atthe point of entrance into said succeeding zone which comprises:Vmaintaining a pressure differential between the respective zonesdecreasing in the direction of 22' liquid iow, said pressure diterentialbetween any given pair of zones being determined by the formula whereinP1 in p.s.i. is the pressure in one reaction zone; P2 is the pressure(ps-i.) in the next succeeding reaction zone; ale is the averagespecific gravity of the liquid in zone P2; he is the liquid level, infeet, Iof the nliquid in zone P2; df is the specic gravity of theliquidof relatively low density owing from zone P1 to` zone P2; hf isthe liquid level, in feet, of the liquid being transported to 'zone P2and F is the frictional loss during transportation expressed in poundsper square inch.

18. The process of claim 17 wherein the alkylatable hydrocarboncomprises an isoparaiiin. y

19. In an alkylation Yreaction wherein an alkylatable hydrocarbon isreacted withV an olenin the presence of an acid catalyst, wherein thealkylatable hydrocarbon and acid catalyst are emulsiiied and passed forseries dow through a multi-stage reactor containing a plurality ofconned reaction zones with separate olefin introduction into each ofsaid zone for contact with the emulsion, and wherein the temperature ofthe Vreaction is controlled by allowing a portion ofthe reaction mixtureto vaporize in each reaction Zone, the improved process for transferringa liquid mixture comprising alkylatable hydrocarbon and acid catalyst ata lowdensity from one reaction zone into a succeeding reaction Zonecontaining liquid of relatively high density at the point of entranceinto said succeeding zone which comprises: maintaining a pressuredifferential between the respective zones decreasing in the direction ofliquid iiow, said pressure differential between any given pair of zonesbeing determined by the formula v (dhdwddh) P 1- P2 2.31 -l- F whereinP1 is the pressure (psi.) in one reaction zone; P2 is the pressure(psi.) in the next succeeding reaction zone; de is the average specificgravity of the liquid in zone'P2; he is the liquid level in feet of theliquid in zone lf2; df is the speciiic gravin of the liquid ofrelatively low density flowing from zone P1 to zone P2; hf is the liquidlevel in feet of the liquid being transported to zone P2 and F is thefrictional loss during transportation expressed in pounds per squareinch, said pressure diierential being maintained by separate withdrawalof a controlled amount of vapors from each of the zones in themulti-zone reactor.

20. The process of claim 18 wherein the alkylatable hydrocarboncomprisess an isoparafn.

2l. The process of claim 2O wherein the isoparaflin comprises isobutaneand the olefin comprises butene.

22. The process of claim 18 wherein the acid catalyst comprises sulfuricacid.

23. A method for eiecting the exothermic alkylation of an iosparaiiinhydrocarbon in the presence of a liquid acid catalyst which comprises:maintaining a body of liquid comprising amixture oi isopara'in and acidcatalyst within a reactor containing a plurality of confined reactionzones; circulating said mixture in each of saidzones upwardly throughand downwardly around a path of restricted cross-sectional area betweena point adjacent the lower boundary of the liquid body and a point nearthe upper boundary thereof; introducing an alkylating agent into theliquid mixture at a point of such high upward vertical iiow velocitythat the isopararlin and acid are emulsiiied; allowing the exothermicalkylation reaction to take place while simultaneously vaporizing aportion of the liquid mixture to control the temperature of theexothermic reaction; maintaining a body of vapor above the body ofliquid which body of vapor is conned in the reaction zone in which it isformed; withdrawing the liquid mixture at a point adjacent its upperboundary and transferring said liquid through a confined passageway andinto the bottom portion of the next succeeding v reaction zone;repeating the above procedure in each of 23 the reaction zones withinthe reactor; passing the liquid mixture containing alkylate product fromthe iinal reaction Zone to a separation zone and separating alkylateVfrom the liquid mixture. n 24. The process of claim 23 wherein thecatalyst comprises sulfuric acid.

25. The process of claim 23 wherein the isoparaiin comprises isobutane,Y

26The process of claim 23 wherein the olefin cornprises butene.

27. The processes of claim 23 wherein the liquid mixture afterintroduction of oleiin is passed upwardly in a plurality of elongatedquiescent zones and then passed downwardly outside of said elongatedpassageways.

28. The process of claim 23 wherein the circulation of liquid upwardlyand downwardly in each of said reaction zones is induced by a mixingzone adjacent the lower boundary of the liquid body.

29. The process of claim 23 wherein the liquid in one reaction zone isinduced to flow into the next succeeding reaction Zone by maintaining apressure drop of atleast 1 p.s.i.g. between the zones, the pressuredecreasing in,V

the direction of liquid flow.

30. A method for effecting the exotherrnic alirylation of an isoparatiinhydrocarbon in the presence of a liquid acid catalyst which comprises:maintaining a body of liquid comprising a mixture of isoparatiin andacid catalyst within a reactor containing a plurality of confined retrolthe temperature of the exothermic reaction and to provide isothermalconditions throughout the reaction zone; maintaining a body of vaporabove the body Vof. liquid, which body of vapor is confined in `thereaction zone in which it is formed; withdrawing the liquid mixture at apoint adjacent its upper boundary and transferring said liquid through aconiined passageway into the bottom portion of the next succeedingreaction zone; and repeating the above procedure in each of the reactionzones within the reactor.

31. VIn an exothermic condensation reaction wherein a lirst liquidcomponent is reacted withk a second liquid component in the presence ofan immiscible liquid catalyst, the steps comprising: introducing saidfirst liquid componentV and said liquid catalyst into a iirst reactionzone, intimately mixing said catalyst and alkylatable hydrocarbon insaid reaction zone to produce an emulsied liquid body; introducing saidsecond liquid component into said emulsion to eiect the reaction of saidrst and second liquid components in the liquid phase; owing a portion ofthe resulting liquid body contained in said first reaction zone, in aconned stream, into a second reaction Zone at a low point therein,intimately mixing said liquid to maintain an emulsion in said secondreaction zone; introducing additional second liquid component into saidsecond reaction zone to eiect reaction thereof with said emulsion;maintaining over the body of liquid in each of said reaction zones, aseparate coniined vapor phase comprising vapors evolved from the liquidby the heat of reaction; separately withdrawing a controlled amount ofvapors from each of said vapor phases; and maintaining a higher pressureon the Vapor phase over the liquid body contained in said rst reactionzone than the pressure maintained on the vapor phase over the liquidbody contained in said second reaction zone to produce a regulated ilowof Said liquid, in said confined stream, from said iirst recation zonetoisaid second reaction zone.

References Cited in the le of this patent UNITED STATES PATENTS2,238,802 Altshuler et al Apr. 15, 1941 2,244,556 Holm June 3, 19412,366,627 Kemp Jan. 2, 1945 2,429,205 Jenny et al. Oct. 2l, 19472,474,924 Watson et al. Iuly 5, 1949 2,768,987 Hart Oct. 30, -19562,920,124 Stiles et al. Jan. 5, 1960 2,927,009 Stiles et al. Mar. 1,1960 FOREIGN PATENTS 763,314 Great Britain Dec. 12, 1956 *UNITED-sTA'rEsa-.PATENI OEFIEE CEE-mima oFfcoRnEcf-HON n -l .Patent Noor3.,..16Ovj6732 I 'Y l n DPC erbeiviv 8", n 'A l I I l John 'Mg :Black etal; .I v y n Itis hereby certified that error appears in the. abovex-/nzmmbered patn ent requiring' correotion and `that the said LettersPatent shouldread as corrected below. l n

In the grant, lines 3 and 4, and in the heading to 'the printedspecification, lines 5 and 6, for "assgnors, by mesne assignments .toPullman Incorporate-d, a corporation off'f Delaware", eachf oocurrence,read assgnors to"'Pullman Incorporated, a corporation of DelawareSignedv and sealed this 7th'da-y of, June 1966.

(SEAL) Attest y ERNEST w. sw'lDEE EDWARD J. BRENNER Attesting OfficerCommissioner of Patents t

1. IN AN ALKYLATION REACTION HEREIN AN ALKYLATABLE HYDROCARBON ISREACTED WITH AN ALKYLATING AGENT IN THE PRESENCE OF AN IMMISCIBLE LIQUIDCATALYST IN A SERIES OF CONFINED MIXING ZONES EACH CONTAINED IN ACONFINED REACTION ZONE, AND WHEREIN THE ALKYLATABLE HYDROCARBON AND THECATALYST ARE PORGRESSIVELY PASSED IN SERIES FLOW THROUGH EACH OF THEREACTION ZONES AND THEIR RESPECTIVE MIXING ZONES, THE PROCESS WHICHCOMPRISES: PASSING THE ALKYLATIABLE HYDROCARBON AND THE LIQUID CATALYSTTO THE LOWER PORTION OF A FIRST REACTION ZONE AND A CONFINED SPACEDIRECTLY BELOW AN AREA OF HIGH UPWARD VERTICAL VELOCITY; EMULSIFYING THEALKYLATABLE HYDROCARBON AND THE LIQUID CATALYST; PASSING THE EMULSIONUPWARDLY AT MAXIMUM VELOCITY WITHIN A FIRST CONFINED MIXING ZONE PAST APOINT WHERE THE ALKYLATING AGENT IS CONTINUOUSLY BEING INTRODUCED, UNDERCONDITIONS SUCH THAT THE CONDENSATION REACTION BETWEEN THE ALKYLATABLEHYDROCARBONS AND ALKYLATING AGENT TAKES PLACE IN THE LIQUID PHASE ANDSPONTANEOUS VAPORIZATION OCCURS; PASSING THE RESULTING MIXTURE UPWARDLYTHROUGH A SEMIQUIESCENT ZONE TO SEPARATE THEREFROM VAPOROUS MATERIAL;ACCUMULATING IN AND VENTING VAPORS FROM THE UPPER PORTION OF SAID FIRSTMIXING ZONE; REVERSING THE FLOW OF THE LIQUID MIXTURE IN A DOWNWARDLYDIRECTION WITHIN SAID FIRST MIXING ZONE, AND EXPELLING THE LIQUIDMIXTURE FROM A LOWER PORTION OF THE FIRST CONFINED MIXING ZONE;RECIRCULATING A PORTION OF THE EXPELLED LIQUID TO SAID AREA OF HIGHUPWARD VERTICAL VELOCITY IN ADMIXTURE WITH THE INCOMING ALKYLATABLEHYDROCARBON AND CATALYST; RECIRCULATING THE EXPELLED LIQUID THROUGH THEFIRST CONFINED MIXING ZONE FOR RECONTACT WITH THE ALKYLATING AGENT;ALLOWING THE LDIQUID LEVEL IN SAID FIRST REACTION ZONE TO RISE TO APREDETEREMINED LEVEL ABOVE THE POINT WHERE LIQUID IS EXPELLED FROM THECONFINED MIXING ZONE; TRANSFERRING LIQUID ABOVE SAID LIQUID LEVEL INSAID FIRST REACTION ZONE THROUGH A CONFINED PASSAGEWAY AND THENCE TO ASECOND CONFINED SPACE DIRECTLY BELOW AN AREA OF HIGH UPWARD VERTICALVELOCITY IN A SECOND CONFINED REACTION ZONE CONTAINING A SECOND CONFINEDMIXING ZONE; REPREATING THE ABOVE FLOW AND TRANSFER OF LIQUID IN EACH OFTHE SUCCEEDING ZONES AND SEPARATELY WITHDRAWING A CONTROLLED AMOUNT OFVAPORS FROM EACH OF THE CONFINED REACTION ZONES TO REGULATE THE PRESSURETHEREIN SO THAT THE PRESSURE PROGRESSIVELY DECREASES IN THE DIRECTION OFLIQUID FLOW THROUGH THE REACTION ZONES TO INDUCE THE FLOW OF LIQUIDTHROUGH SAID ZONES.